Air filter assemblies for internal combustion engines



0a. 21, 1969 K. E. BUCKMAN 3,473,301

AIR FILTER ASSEMBLIES FOR INTERNAL COMBUSTION ENGINES Filed Nov. 13, 1967 2 Sheets-Sheet 1 HIHIID a Inventor /%?227e/% faves! fizzciman tlorney Oct. 21, 1969 K. E. BUCKMAN 3,473,301

AIR FILTER ASSEMBLIES FUR INTERNAL COMBUSTION ENGINES Filed Nov. 13, 1967 2 Sheets-Sheet 2 Inventor QzfW Alfarney United States Patent "ice 3,473,301 AIR FILTER ASSEMBLIES FOR INTERNAL COMBUSTION ENGINES Kenneth Ernest Buclkman, Southampton, England, as-

signor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Nov. 13, 1967, Ser. No. 682,322 Claims priority, application Great Britain, Nov. 17, 1966, 51,559/ 66 Int. Cl. B01d 46/42 US. Cl. 55-510 1 Claim ABSTRACT OF THE DISCLOSURE In order to improve the attachment of the cover of a plastics air cleaner to the air cleaner casing the cover is formed with an annular skirt and a radial flange and is stiffened by means of internal radial ribs, the arrangement ensuring that, when the cover is secured by a central bolt the shoulder on the cover which engages one end of the filter element acts as a fulcrum so that the skirt is levered into tighter engagement with the casing as the cover is tightened down by the fixing bolt.

This invention relates to air filter assemblies for internal combustion engines and in particular to the housing for the filter element of the assembly.

Housings for air filter elements for use on internal combustion engines commonly comprise upper and lower shells which are secured together by a central nut and bolt so as to clamp together the upper and lower shells at their respective rims and clamp the filter element between annular shoulders formed in the shells between their respective centres and peripheral portions.

A difliculty which arises when such filter housings are made of plastics material is that the clamping together of the two shells, owing to the relative flexibility of the plastics material, results in a reduction in the effective contact pressure between the rims of the shells and this may give rise to undesirable vibration and noise, as well as impaired sealing.

In an air filter assembly according to the invention, the housing for the air filter element comprises an upper and a lower shell of general shallow cup form adapted to be secured together by a central fastening such as a nut and bolt, the shells having between their respective centres and their outer peripheries continuous shoulders between which the opposite ends of the filter element are adapted to be clamped so as to be sealed thereto when the shells are secured together, the upper shell having an elongated peripheral skirt extending below the lower edge of an adjacent radial flange, said skirt being a sliding fit within the wall of the lower shell and said flange being adapted to engage the upper edge of the lower shell when the two shells are interengaged.

An annular gasket may be clamped between the upper edge of the lower shell and the annular flange on the upper shell.

The upper shell preferably has a plurality of radial ribs extending from an upper portion thereof, of less than the full shell diameter, to the lower edge of said skirt at a plurality of angularly spaced positions around the centre of the shell; and with this construction the skirt may be formed with a reduced thickness in the portions thereof intermediate the ribs, such reduction thickness facilitating the deformation of the skirt into tight engagement with the wall of the lower shell when the two shells are clamped together.

The scope of the invention is defined by the appended claims; and the invention and the method by which it is to be performed are hereinafter particularly described 3,473,301 Patented Oct. 21, 1969 with reference to the accompanying drawings in which:

FIGURE 1 is a vertical section through an air filter assembly according to the invention;

FIGURE 2 is a partial plan of FIGURE 1; and

FIGURE 3 is a detail view showing the effect of clamping the upper shell on to the lower shell.

FIGURES 1 and 2 show an internal combustion engine air cleaner or filter assembly 1 comprising an upper shell 2 and a lower shell 3 detachably secured together by a bolt 4 which extends through an opening 5 in the upper shell 2 and is screwed into a threaded opening 6 in a bail or bridge member 7 which is fixed in the air intake tube 8 of an internal combustion engine (not shown) on which the air filter assembly 1 is fitted. The shells 2 and 3 are moulded from a plastics material such as polypropylene.

The lower shell 3 has in its base an outlet passage 9 in an integral tubular neck 10 the lower end of which abuts a shoulder 11 on the intake tube 8.

The base of the lower shell 3 is formed with an annular shoulder 12 which extends around the outlet passage 9, and the upper shell 2 is formed with a similar shoulder 14, the opposite ends of a tubular filter element 15 being clamped between the shoulders 12, 14 when the shells are secured together as shown in FIGURE 1. Annular gaskets 16, 17 are respectively interposed between the shoulders 12, 14 and the adjacent ends of the filter element 15.

The lower shell 3 is formed with an integral intake pipe 18 extending from its side wall and may also be formed, as shown, with a subsidiary intake pipe 19 which may be connected to the engine crankcase to extract fumes therefrom. The pipe 19 is shown in FIGURE 1 angularly displaced from its true position, (shown in FIGURE 2), to simplify the drawing.

The upper shell 2 is formed with a peripheral dependent skirt 20 adjacent an integral flange 21 which is of inverted L shape, one part of the flange 21 adjacent the skirt 20 extending radially and continuing into a downwardly extending part between which and the skirt 20 is formed an annular recess in which engages the upper end 22 of the wall of the lower shell 3.

The shell 2 is also formed with a plurality of radial ribs 23 which extend toward the shoulder 14 from the lower end of the skirt 20; and the central part of the shell 2 also has a plurality of radial ribs 24 moulded integral therewith.

With the construction described above, the pulling down of the upper shell 2 into engagement with the lower shell 3 by the central fastening bolt 4 causes the skirt 20 on the upper shell 2 to be tilted so that its lower portion is forced outwardly into more secure engagement with the wall of the lower shell 3, the shoulder 14 of the upper shell engaged with the end of the filter element 15 clamped between the shells acting as a fulcrum to assist such clamping action between the skirt and the wall of the respective shells. The position of the shell 2 relative to the upper end of the filter element, before the bolt 4 is tightened, is shown in FIGURE 3.

The upper portion 22 of the wall of the lower shell 3 is retained in the annular groove between the skirt 20 and flange 21, thereby preventing outward deflection of the upper wall portion 22 and maintaining the sealing between the shell walls.

To assist in the formation of the shells 2, 3 the skirt 20 and the upper wall portion 22 of the complementary shells 2, 3 respectively are formed with complementary draught or taper on their interengageable surfaces, the draught on the upper shell 2 preferably being less than the draught on the lower shell 3 so as to permit contact between the lower edge of the skirt 20 with the inner wall of the lower shell 3 at a point below the upper edge of the lower shell and ensure an interference fit between 3 the skirt 20 and the wall of the shell 3 without requiring unduly fine dimensional tolerances.

I claim:

1. An air cleaner assembly for an internal combustion engine having an air inlet tube, comprising: a housing including an upper annular shell and a lower annular shell each formed of flexible plastic material; an air intake pipe and an air outlet formed in said lower shell, said air outlet registering with said air inlet tube, annular shoulders formed on said upper and lower shells extending toward each other between the center and outer sides of said shells, an annular filter element positioned about said shoulders and in sealed relationship with said upper and lower shells and extending between said air intake pipe and said air outlet; an upwardly extending outer annular wall extending from the bottom wall of the lower shell and terminating at the to with an annular rim; an elongated downwardly depending annular skirt formed on said upper shell, said skirt being slidably received in said lower shell below said rim with an outwardly facing surface thereof adjacent an inwardly facing surface of said upwardly extending outer wall; an annular groove formed in said upper shell extending radially outward of said skirt and positioned adjacent said rim, said rim being received and retained in said groove; first fastener means connected to said air inlet tube and second fastener means extending through the centers of said upper and lower shells into said first fastening means to cause said skirt on said upper shell to tilt and provide a sealing engagement with said outer annular wall.

References Cited UNITED STATES PATENTS 3,076,555 2/1963 Jackson et al. 210-493 3,190,058 6/1965 Farr et al. -498 2,954,091 9/1960 McMichael 55-276 3,003,637 10/1961 Buckman 55-510 3,235,633 2/1966 Holloway et al. 55-502 3,277,876 10/1966 Abts 55-502 3,355,863 12/1967 Pittsley 55276 3,385,038 5/1968 Davis 55-502 FOREIGN PATENTS 894,235 4/1962 Great Britain. 1,147,736 6/1957 France. 1,358,644 3/1964 France.

926,698 5/ 1963 Great Britain.

HARRY B. THORNTON, Primary Examiner BERNARD NOZICK, Assistant Examiner 

